The present invention relates to a device for acoustic rodent control.
It is known that currently commercially available rodent control methods include some that use sound vibrations emitted by particular devices; these vibrations are perceived by rodents, which move away from the covered area because they are stressed by such vibrations.
Italian patent No. 1288012 by the same Applicant discloses a diffuser for acoustic rodent control devices that is substantially constituted by a solid of revolution shaped so as to form three annular peripheral rings which are mutually axially spaced, with an upper concave surface and a lower recess.
A piezoelectric device, controlled by an electronic circuit, is applied inside the lower recess.
The recess is then closed by a cover that is provided with a central hole having a threaded axial shank, for fixing the body to a support.
The diffuser allows to convert the structural noise generated internally by the piezoelectric element into airborne noise without openings or auxiliary devices such as loudspeakers, with a great benefit in terms of mechanical safety and reliability, for use in the most challenging operating conditions required by the various applications.
Although considerable advantages are obtainable by the use of a diffuser as described above, said diffuser entails drawbacks.
There is in fact absolutely no centralized control over a set of transducers.
Moreover, the cavity of the diffuser that contains the piezoelectric element is too small.
The dynamic system of the piezoelectric element is in fact very critical, since the vibratory state of the ceramic wafer generates a beam of vibrations which, reflected by the metallic cover, return toward the wafer, applying a contrast force to the piezoelectric element, which thus abandons the base frequency and eliminates the efficiency of the system.
In this manner, the piezoelectric element has a very short life.
Further, the cavity of the diffuser is too small even for the space occupied by an electronic board.
In order to eliminate the acoustic pressure that is generated in the cavity, a hole is provided in the cover.
However, this remedy caused loss of watertightness of the cavity, with a consequent rapid oxidation of the ceramics of the piezoelectric element, further reducing its life.